Question

What two numbers multiply to get 25 and add to -10

Answer 1

$x;\ y-the\ numbers\\\\ \left\{\begin{array}{ccc}xy=25\\x+y=-10&\to x=-10-y\end{array}\right\\\\subtitute:\\(-10-y)y=25\\(-10)(y)-y(y)=25\\-10y-y^2=25\\-y^2-10y-25=0\ \ \ \ |change\ the\ signs\\y^2+10y+25=0\\y^2+5y+5y+25=0\\y(y+5)+5(y+5)=0\\(y+5)(y+5)=0\\(y+5)^2=0\iff y+5=0\to \boxed{y=-5}\\\\subtitute\ the\ value\ of\ y\ to\ the\ equation\ x=-10-y\\x=-10-(-5)\\x=-10+5\\\boxed{x=-5}\\\\Answer:\boxed{-5\ and\ -5}$